1. Field of the Invention
This invention relates to a technique for high-sensitivity high-precision imaging and size reduction of an imaging apparatus used for a dry image recording system.
2.Description of the Related Art
Imaging apparatus for obtaining diagnostic hard copy images by digital radiography using storage phosphor imaging plates, CT imaging, MR imaging, etc. have adopted a wet system wherein a silver salt photographic material is exposed and wet-processed.
On the other hand, a dry system recording apparatus involving no wet chemical processing has recently engaged attention. Light-sensitive and/or heat-sensitive heat-developable photographic materials or heat-developable photographic films (hereinafter inclusively referred to as heat-developable light-sensitive materials) are used in a dry system recording apparatus. In a dry system recording apparatus, a heat-developable light-sensitive material is irradiated (scanned) with a laser beam to form a latent image in an image exposure section, brought into contact with a heating means to perform heat development in a heat development section, and discharged out of the apparatus.
The dry system is advantageous in that image formation completes in a shorter time than in a wet system and that the issue of waste liquid disposal is not involved, and is fully expected to enjoy an increasing demand.
Heat-developable light-sensitive materials that have been used in a conventional dry system have a silver halide spectrally sensitized to the infrared or red region. However, spectrally sensitized heat-developable light-sensitive materials undergo desensitization during storage due to gradual decomposition of the spectral sensitizers with time.
JP-A-12-305213, filed by the same applicant as the present invention, suggests that the problem is settled by exposing a silver halide which is not spectrally sensitized to an ultraviolet to blue laser beam. Nevertheless, the method disclosed failed to design a sufficiently sensitive system and was insufficient for assuring necessary image quality, i.e., sharpness.